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The Sagrada Familia church in Barcelona, Spain, is seen under construction during World Earth Hour, March 28, 2015.

Work on Barcelona's breathtaking La Sagrada Familia Basilica, designed by visionary architect Antoni Gaudi, has entered its final phase of raising six immense towers that will make it Europe's tallest religious building, surpassing Germany's Ulm Minster.

Presenting the project Thursday, chief architect Jordi Fauli said the central "Tower of Jesus Christ," the tallest of the six, will make the architectural marvel that draws millions of visitors each year one for the record books when it is finished in a little over a decade.

"The central tower of 172.5 meters (566 feet) will make it the tallest cathedral in Europe, because the tallest tower in Europe is Ulm, at 162 meters (531.5 feet)," Fauli said.

St. Peter's Basilica in Rome will still have the tallest interior.

The Sagrada Familia, an emblematic fixture of the Barcelona skyline and a major tourist site, had its first stone laid in 1882. It is 70-percent complete and currently tops out at 112 meters (367 feet).

Fauli said the plan to have the towers and most of the church's structure completed in 2026 for the 100th anniversary of Gaudi's death is still on schedule. He said there will still be some elements left to finish, such as decorations.

"It's difficult to predict but we can say that it will be completed by 2030, 2032," he said.

The "Tower of Jesus Christ" will be crowned by a cross and tightly surrounded by five other towers, one dedicated to Mary and four slightly shorter ones for the four evangelists.

Fauli unveiled the next phase of the construction in a newly finished chamber that formed a small amphitheater, perched 60 meters (196 feet) above the floor of the church from where hundreds of visitors gazed at the church's stained glass windows and arching ceilings.

The tower will rise directly above the chamber, which is designed to support the weight of the towers and channel sunlight into the building.

An inside view of the basilica of the Sagrada Familia by Antoni Gaudi in Barcelona, Spain on October 21, 2015.
Photo credit: Getty

A mere 15 years ago, there was no roof on the inner part of the church as it stood between the two beautiful facades with eight bell towers that leave spectators overcome with awe, one side looking like a sand castle and the other a work of art inspired by cubist painting.

Gaudi won the patronage of some of Barcelona's wealthiest industrialist and upper-crust families, who commissioned him to build gorgeous homes and other daring buildings and parks that have helped make Barcelona a leading tourist destination.

A fervent Catholic, Gaudi largely dedicated his life to the project, incorporating both Christian symbolism and organic forms into a unique aesthetic.

Gaudi, who died in 1926 after being struck by a trolley, never expected the cathedral to be completed in his lifetime. Only one facade was finished when he died.

Fauli took over as the chief architect in 2012. He inherited the charge of carrying on the task of making Gaudi's drawings, some of which were only rough sketches, into the massive monument that is now reaching its conclusion.

The monument received more than 3.2 million visits in 2014, making it one of the biggest tourist sites in Spain.